Vibrating meters, such as for example, vibrating densitometers and Coriolis flow meters are generally known and are used to measure mass flow and other information for materials within a conduit. The meter comprises a sensor assembly and an electronics portion. The material within the sensor assembly may be flowing or stationary. Each type of sensor may have unique characteristics, which a meter must account for in order to achieve optimum performance. For example, some sensors may require a flow tube apparatus to vibrate at particular displacement levels. Other sensor assembly types may require special compensation algorithms.
The meter electronics typically include stored sensor calibration values for the particular sensor being used. The meter electronics uses these sensor calibration values in order to accurately measure mass flow rate and density. The sensor calibration values can comprise calibration values derived from measurements under test conditions, such as at the factory. Therefore, each sensor type can have unique calibration values.
Exemplary Coriolis flow meters are disclosed in U.S. Pat. Nos. 4,109,524, 4,491,025, and Re. 31,450 all to J. E. Smith et al. These flow meters have one or more conduits of straight or curved configuration. Each conduit configuration in a Coriolis mass flow meter has a set of natural vibration modes, which may be of simple bending, torsional, or coupled type. Each conduit can be driven to oscillate at a preferred mode.
Material flows into the flow meter sensor assembly from a connected pipeline on the inlet side of the sensor, is directed through the conduit(s), and exits the sensor through the outlet side of the sensor. The natural vibration modes of the vibrating, material filled system are defined in part by the combined mass of the conduits and the material flowing within the conduits.
When there is no flow through the sensor, a driving force applied to the conduit(s) causes all points along the conduit(s) to oscillate with identical phase or a small “zero offset”, which is a time delay measured at zero flow. As material begins to flow through the sensor, Coriolis forces cause each point along the conduit(s) to have a different phase. For example, the phase at the inlet end of the sensor lags the phase at the centralized driver position, while the phase at the outlet leads the phase at the centralized driver position. Pick-off sensors on the conduit(s) produce sinusoidal signals representative of the motion of the conduit(s). Signals output from the pick-off sensors are processed to determine the phase difference between the pick-off sensors. The phase difference between the two or more pick-off sensors is proportional to the mass flow rate of material flowing through the conduit(s).
The mass flow rate of the material can be determined by multiplying the phase difference by a Flow Calibration Factor (FCF). Prior to installation of the sensor assembly of the flow meter into a pipeline, the FCF is determined by a calibration process. In the calibration process, a fluid is passed through the flow tube at a known flow rate and the relationship between the phase difference and the flow rate is calculated (i.e., the FCF). The sensor assembly of the flow meter subsequently determines a flow rate by multiplying the FCF by the phase difference of the pick-off sensors. In addition, other calibration factors can be taken into account in determining the flow rate.
Many vibrating meter applications comprise a vibrating sensor network that may include multiple sensors operating within a communication network of some manner. The network commonly includes a sensor monitoring system that gathers measured flow data and controls and coordinates operations of various sensors. The network may include vibrating sensors of different sizes, models, model years, and electronics and software versions. One problem faced by users of meters is the ability to correctly identify the particular sensor component being used with the meter electronics. Various prior art attempts exist such as manually entering the model/type of the sensor into the meter electronics, having the meter electronics obtain the sensor type data from the sensor in the form of a readable code or identifier stored in a memory included in the sensor, obtaining calibration data for the sensor to identify the type of sensor, etc. These prior art attempts are disclosed in U.S. Pat. No. 7,523,639, assigned on its face to Micro Motion, Inc., which is hereby incorporated by reference. However, while these prior art approaches can identify various types of sensors, manufacturers still face competition by “knock-off” sensor assemblies, i.e., unauthorized copies of sensor assemblies, that are used with the manufacturer's meter electronics. Customers may be confused and believe they are using a particular manufacturer's meter, when in fact, they are using only a portion of the manufacturer's meter. For example, a user may be utilizing a meter electronics manufactured and sold by Micro Motion, Inc. while the sensor assembly of the vibrating meter is manufactured by another company. As a result, the vibrating meter will not perform according to Micro Motion's standards. This not only reduces the sales by the manufacturer, but can also weaken the manufacturer's brand name recognition if the knock-off sensor does not meet the manufacturer's quality and accuracy standards.
Prior to the present invention, restricting a customer's use of particular meter electronics with a knock-off sensor was difficult if not impossible so long as the customer was able to input the correct calibration information for the sensor into the meter electronics. Even in prior art approaches where calibration values for the sensor were obtained, the approach did not restrict the use of the meter electronics. For example, the '639 patent mentioned above, discloses a flow meter type identification where calibration values for the sensor assembly of the flow meter are received and correlated to known sensor calibration values. Based on the correlation, the sensor type is identified. The problem with this approach is that the sensor type is simply selected by the calibration values that most closely match the stored values. Therefore, even if the calibration values received by the meter electronics do not match a stored value corresponding to a particular sensor type, the system simply assumes that the sensor comprises the sensor type with the closest calibration values and that the error is due to some anomaly in the manufacturing process or calibration process. Consequently, a knock-off sensor can be used even with the approach disclosed by the '639 patent.
The present invention solves this and other problems and an advance in the art is achieved. The present invention validates a sensor type by comparing one or more received calibration values to known calibration values. If the one or more received calibration values fall outside of a predetermined tolerance, the meter electronics rejects the sensor as comprising an invalid sensor type. For example, the sensor may comprise an invalid sensor type if it is manufactured by a different company.